4. Find the surface area of the unshapened portion

A pencil of radius 3.5 \(cm\) sharpened at one edge is of length 29 \(cm\). If the length of the sharpened portion is 0.5 \(cm\), then find the lateral surface area of the unsharpened portion.

 

 

Answer:

 

The lateral surface area of the unsharpened portion is  \(cm^2\).

 

[Note: If the answer is a whole number, enter as it is. If not, enter the answer up to two decimal places.]